Embedding layer in neural network for ranking candidates

ABSTRACT

In an example embodiment, a platform is provided that utilizes information available to a computer system to feed a neural network. The neural network is trained to determine both the probability that a searcher would select a given potential search result if it was presented to him or her and the probability that a subject of the potential search result would respond to a communication from the searcher. These probabilities are essentially combined to produce a single score that can be used to determine whether to present the searcher with the potential search result and, if so, how high to rank the potential search result among other search results. In a further example embodiment, embeddings used for the input features are modified during training to maximize an objective.

TECHNICAL FIELD

The present disclosure generally relates to computer technology for solving technical challenges in machine learning. More specifically, the present disclosure relates to an embedding layer in a neural network.

BACKGROUND

The rise of the Internet has given rise to two different, yet related, phenomena: the increase in the presence of social networks, with their corresponding member profiles visible to large numbers of people, and the increase in the desirability of reaching out to small groups of social network members who meet strict criteria. This is especially pronounced in the field of recruiting, where recruiters are typically attempting to find members with particular qualifications (e.g., education, experience, skills, etc.) and then generally the recruiters reach out to members with the particular qualifications to find out whether or not the members may be willing to apply for the job openings the recruiter has available.

Job solicitation communications, such as emails sent by recruiters to members who may be prospective job applicants, can take a lot of time on the part of the recruiters, especially if done effectively. Effective job solicitation communications generally include personalized information about the member and have the solicitation geared specifically towards that member, thus making it look less like a mass communication sent to many potential applications and more like the recruiter has specifically targeted the member. Recruiters, however, have a limited amount of time to spend in creating such job solicitation communications, and thus would benefit greatly if mechanisms were in place to reduce the likelihood that such time would be wasted. A technical problem arises, however, in determining whether a particular member, gauged from information available to a computer system, is likely to respond to a particular communication, and even if such a determination were feasible, how to utilize such information to reduce wasted resources. Additionally, a recruiter would also benefit if he or she were presented with candidate results of candidates that the recruiter is likely to want to contact. Another technical problem arises in determining whether a particular recruiter is likely to want to contact a particular member.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the technology are illustrated, by way of example and not limitation, in the figures of the accompanying drawings.

FIG. 1 is a block diagram illustrating a client-server system, in accordance with an example embodiment.

FIG. 2 is a block diagram showing the functional components of an online service, including a data processing module referred to herein as a search engine, for use in generating and providing search results for a search query, consistent with some embodiments of the present disclosure.

FIG. 3 is a block diagram illustrating an application server module of FIG. 2 in more detail.

FIG. 4 is a block diagram illustrating the search result generator of FIG. 3 in more detail, in accordance with an example embodiment.

FIG. 5 is a diagram illustrating a Deep Convolutional Neural Network (DCNN), in accordance with an example embodiment.

FIG. 6 is a flow diagram illustrating a method of training a DCNN, in accordance with an example embodiment.

FIG. 7 is a block diagram illustrating a neural network, in accordance with an example embodiment.

FIG. 8 is a flow diagram illustrating a method for returning search results in an online computer system, in accordance with an example embodiment.

FIG. 9 is a screen capture illustrating a graphical user interface (GUI) for displaying results of the ranking performed in FIG. 8.

FIG. 10 is a block diagram illustrating an architecture of software, which can be installed on any one or more of the devices described above.

FIG. 11 illustrates a diagrammatic representation of a machine in the form of a computer system within which a set of instructions may be executed for causing the machine to perform any one or more of the methodologies discussed herein, according to an example embodiment.

DETAILED DESCRIPTION

Overview

In an example embodiment, a platform is provided that utilizes information available to a computer system to feed a neural network. The neural network is trained to determine both the probability that a searcher would select a given potential search result if it was presented to him or her and the probability that a subject of the potential search result would respond to a communication from the searcher. These probabilities are essentially combined to produce a single score that can be used to determine whether to present the searcher with the potential search result and, if so, how high to rank the potential search result among other search results.

In a further example embodiment, embeddings used for the input features are modified during training to maximize an objective. An embedding is a representation of a value of a feature in a dimensional space, which allows the neural network to perform distance-related measurements when comparing two values of features. The embeddings may have been initially applied to the input values, but then are essentially fine-tuned automatically during training on the change embeddings. While initial embeddings are often based on co-occurrence in a sample data set, it may be that input values that co-occur frequently and thus may be similar generally may, for example, mean something completely different to a recruiter. Fine-tuning the embeddings allows the neural network to more accurately train for such situations.

This fine tuning may be performed in an embedding layer. This embedding layer includes functionality for deriving additional embeddings that are not initially applied as input values, such as embeddings of text in candidate profiles. This leverages the neural network to perform natural language understanding of unstructured profile text. Fine tuning is then also applied to these learned embeddings of natural language text. In an example embodiment, the natural language processing is performed by a separate machine learned model that feeds its output to the neural network to apply embeddings.

Furthermore, since as will be seen the neural network uses multiple types of input features, such as candidate features (features of, for example, individual members) and query features (features specified in a search query from, for example, a recruiter), in situations where there is a shared feature between the different input feature types, in an example embodiment embedding weights that have been learned/fine-tuned may then also be shared. This results in fewer parameters being fed to the neural network, which improves performance metrics and also prevents overfitting.

Additionally, the ranking of candidates performed during both training and runtime of the neural network may be accomplished via listwise analysis, as opposed to, for example, pairwise or pointwise analysis.

DESCRIPTION

The present disclosure describes, among other things, methods, systems, and computer program products that individually provide functionality for one or more machine learning algorithm models. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the various aspects of different embodiments of the present disclosure. It will be evident, however, to one skilled in the art, that the present disclosure may be practiced without all of the specific details.

FIG. 1 is a block diagram illustrating a client-server system 100, in accordance with an example embodiment. A networked system 102 provides server-side functionality via a network 104 (e.g., the Internet or a wide area network (WAN)) to one or more clients. FIG. 1 illustrates, for example, a web client 106 (e.g., a browser) and a programmatic client 108 executing on respective client machines 110 and 112.

An application program interface (API) server 114 and a web server 116 are coupled to, and provide programmatic and web interfaces respectively to, one or more application servers 118. The application server(s) 118 host one or more applications 120. The application server(s) 118 are, in turn, shown to be coupled to one or more database servers 124 that facilitate access to one or more databases 126. While the application(s) 120 are shown in FIG. 1 to form part of the networked system 102, it will be appreciated that, in alternative embodiments, the application(s) 120 may form part of a service that is separate and distinct from the networked system 102.

Further, while the client-server system 100 shown in FIG. 1 employs a client-server architecture, the present disclosure is, of course, not limited to such an architecture, and could equally well find application in a distributed, or peer-to-peer, architecture system, for example. The various applications 120 could also be implemented as standalone software programs, which do not necessarily have networking capabilities.

The web client 106 accesses the various applications 120 via the web interface supported by the web server 116. Similarly, the programmatic client 108 accesses the various services and functions provided by the application(s) 120 via the programmatic interface provided by the API server 114.

FIG. 1 also illustrates a third party application 128, executing on a third party server 130, as having programmatic access to the networked system 102 via the programmatic interface provided by the API server 114. For example, the third party application 128 may, utilizing information retrieved from the networked system 102, support one or more features or functions on a website hosted by a third party. The third party website may, for example, provide one or more functions that are supported by the relevant applications 120 of the networked system 102.

In some embodiments, any website referred to herein may comprise online content that may be rendered on a variety of devices including, but not limited to, a desktop personal computer (PC), a laptop, and a mobile device (e.g., a tablet computer, smartphone, etc.). In this respect, any of these devices may be employed by a user to use the features of the present disclosure. In some embodiments, a user can use a mobile app on a mobile device (any of the machines 110, 112 and the third party server 130 may be a mobile device) to access and browse online content, such as any of the online content disclosed herein. A mobile server (e.g., API server 114) may communicate with the mobile app and the application server(s) 118 in order to make the features of the present disclosure available on the mobile device.

In some embodiments, the networked system 102 may comprise functional components of an online service. FIG. 2 is a block diagram showing the functional components of an online service, including a data processing module referred to herein as a search engine 216, for use in generating and providing search results for a search query, consistent with some embodiments of the present disclosure. In some embodiments, the search engine 216 may reside on the application server(s) 118 in FIG. 1. However, it is contemplated that other configurations are also within the scope of the present disclosure.

As shown in FIG. 2, a front end may comprise a user interface module (e.g., a web server 116) 212, which receives requests from various client computing devices and communicates appropriate responses to the requesting client devices. For example, the user interface module(s) 212 may receive requests in the form of Hypertext Transfer Protocol (HTTP) requests or other web-based API requests. In addition, a member interaction detection module 213 may be provided to detect various interactions that members have with different applications 120, services, and content presented. As shown in FIG. 2, upon detecting a particular interaction, the member interaction detection module 213 logs the interaction, including the type of interaction and any metadata relating to the interaction, in a member activity and behavior database 222.

An application logic layer may include one or more various application server modules 214, which, in conjunction with the user interface module(s) 212, generate various user interfaces (e.g., web pages) with data retrieved from various data sources in a data layer. In some embodiments, individual application server modules 214 are used to implement the functionality associated with various applications 120 and/or services provided by the online service.

As shown in FIG. 2, the data layer may include several databases, such as a profile database 218 for storing profile data, including both member profile data and profile data for various organizations (e.g., companies, schools, etc.). Consistent with some embodiments, when a person initially registers to become a member of the online service, the person will be prompted to provide some personal information, such as his or her name, age (e.g., birthdate), gender, interests, contact information, home town, address, spouse's and/or family members' names, educational background (e.g., schools, majors, matriculation and/or graduation dates, etc.), employment history, skills, professional organizations, and so on. This information is stored, for example, in the profile database 218. Once registered, a member may invite other members, or be invited by other members, to connect via the online service. A “connection” may constitute a bilateral agreement by the members, such that both members acknowledge the establishment of the connection. Similarly, in some embodiments, a member may elect to “follow” another member. In contrast to establishing a connection, the concept of “following” another member typically is a unilateral operation and, at least in some embodiments, does not require acknowledgement or approval by the member that is being followed. When one member follows another, the member who is following may receive status updates (e.g., in an activity or content stream) or other messages published by the member being followed or relating to various activities undertaken by the member being followed. Similarly, when a member follows an organization, the member becomes eligible to receive messages or status updates published on behalf of the organization. For instance, messages or status updates published on behalf of an organization that a member is following will appear in the member's personalized data feed, commonly referred to as an activity stream or content stream. In any case, the various associations and relationships that the members establish with other members, or with other entities and objects, are stored and maintained within a social graph in a social graph database 220.

As members interact with the various applications 120, services, and content made available via the online service, the members' interactions and behavior (e.g., content viewed, links or buttons selected, messages responded to, etc.) may be tracked, and information concerning the members' activities and behavior may be logged or stored, for example, as indicated in FIG. 2, by the member activity and behavior database 222. This logged activity information may then be used by the search engine 216 to determine search results for a search query.

In some embodiments, the databases 218, 220, and 222 may be incorporated into the database(s) 126 in FIG. 1. However, other configurations are also within the scope of the present disclosure.

Although not shown, in some embodiments, the online service system 210 provides an API module via which applications 120 and services can access various data and services provided or maintained by the online service. For example, using an API, an application may be able to request and/or receive one or more navigation recommendations. Such applications 120 may be browser-based applications 120 or may be operating system-specific. In particular, some applications 120 may reside and execute (at least partially) on one or more mobile devices (e.g., phone or tablet computing devices) with a mobile operating system. Furthermore, while in many cases the applications 120 or services that leverage the API may be applications 120 and services that are developed and maintained by the entity operating the online service, nothing other than data privacy concerns prevents the API from being provided to the public or to certain third parties under special arrangements, thereby making the navigation recommendations available to third party applications 128 and services.

Although the search engine 216 is referred to herein as being used in the context of an online service, it is contemplated that it may also be employed in the context of any website or online services. Additionally, although features of the present disclosure are referred to herein as being used or presented in the context of a web page, it is contemplated that any user interface view (e.g., a user interface on a mobile device or on desktop software) is within the scope of the present disclosure.

In an example embodiment, when member profiles are indexed, forward search indexes are created and stored. The search engine 216 facilitates the indexing and searching for content within the online service, such as the indexing and searching for data or information contained in the data layer, such as profile data (stored, e.g., in the profile database 218), social graph data (stored, e.g., in the social graph database 220), and member activity and behavior data (stored, e.g., in the member activity and behavior database 222). The search engine 216 may collect, parse, and/or store data in an index or other similar structure to facilitate the identification and retrieval of information in response to received queries for information. This may include, but is not limited to, forward search indexes, inverted indexes, N-gram indexes, and so on.

FIG. 3 is a block diagram illustrating an application server module 214 of FIG. 2 in more detail. While in many embodiments the application server module 214 will contain many subcomponents used to perform various different actions within the social networking system, in FIG. 3 only those components that are relevant to the present disclosure are depicted. Here, an ingestion platform 300 obtains information from the profile database 218, the social graph database 220, and the member activity and behavior database 222 relevant to a query submitted by a searcher via a user interface server component 302. The user interface server component 302 communicates with a user interface client component 304 located on a client device 306 to obtain this identification information. The details of the user interface client component 304 will be described in more detail below, but generally a user, known hereafter as a searcher, of the user interface client component 304 may begin a search or otherwise cause generation of a search that provides search results of members with whom the searcher may wish to communicate. Information about each of these members is identified in the search results. The user interface server component 302 may generate potential search results based on the query and send identifications of these potential search results to the ingestion platform 300, which can use the identifications to retrieve the appropriate information corresponding to those potential search results from the profile database 218, the social graph database 220, and the member activity and behavior database 222. As will be discussed in more detail below, in some example embodiments, information about the searcher, such as a recruiter, may also be relevant to a prediction from the machine learned models described later. As such, an identification of the searcher may also be communicated via the user interface server component 302 to the ingestion platform 300, which can use the identifications to retrieve the appropriate information corresponding to the searcher from the profile database 218, the social graph database 220, and the member activity and behavior database 222.

The ingestion platform 300 may then provide the relevant information from the profile database 218, the social graph database 220, and the member activity and behavior database 222 to a search result generator 308, which acts to determine which of the potential search results to return and a ranking for those potential search results. In some example embodiments, this information is transmitted in the form of feature vectors. For example, each potential search result may have its own feature vector. In other example embodiments, the ingestion platform 300 sends raw information to the search result generator 308 and the search result generator 308 creates its own feature vectors from the raw information.

The ranked results may then be passed from the search result generator 308 to the user interface server component 302, which acts to cause the user interface client component 304 to display at least a portion of the ranked results.

FIG. 4 is a block diagram illustrating the search result generator 308 of FIG. 3 in more detail, in accordance with an example embodiment. In a training component 400, sample member profiles 402 and sample member activity and behavior information 404 are fed to a feature extractor 406, which acts to extract curated features 408 from the sample member profiles 402 and sample member activity and behavior information 404. Different features may be extracted depending upon whether the member profile is assumed to be that of a prospective search result or that of a prospective searcher.

In an example embodiment, the curated features 408 are then used to as input to a first machine learning algorithm 410 to train a neural network 412 to generate a combined probability that the searcher will select the corresponding potential search result and that the member associated with the corresponding potential search result will respond to a communication from the searcher.

This training may include providing sample search result labels 418 to the first machine learning algorithm 410. Each of these sample search result labels 418 is a binary variable which indicates whether a searcher selected on the corresponding potential search result in the sample member activity and behavior information 404 and/or whether the potential search result responded to a request from the searcher.

In a search result ranking engine 421, candidate records 422 are fed to a feature extractor 424, which acts to extract curated features 426 from the candidate records 422. In some example embodiments, the candidate records 422 include member profile information and member activity and behavior information extracted by the ingestion platform 300, which can use the queries from the user interface server component 302 to retrieve the appropriate information corresponding to potential search results from the profile database 218, the social graph database 220, and the member activity and behavior database 222. The curated features 426 are then used as input to the neural network 412, which outputs a score indicating the probability that the searcher will select the corresponding potential search result and the probability that a member associated with the corresponding potential search result will respond to a communication from the searcher.

This score may be passed to a search result ranker 428, which acts to rank the candidate search results based at least on these probabilities and to return the top n ranked candidate search results.

Thus, the searcher is presented with highly relevant search results based not only on the probability that the search result itself will be of interest to the searcher (based, for example, on the query itself and information about the searcher), but also that the member corresponding to the search result will respond to a communication from the searcher. Therefore, for example, a candidate who might be of extremely high interest to a recruiter but who nevertheless may have a low chance of responding to a communication from the recruiter may not be presented, in favor of a candidate who is of lower interest to the recruiter but has a higher chance of responding to a communication from the recruiter.

Turning now to the creation of the feature vectors, as described earlier the feature vectors may be the same or may be different for the different machine learning algorithm inputs. What follows is a non-exhaustive list of various features that could be included in such feature vector(s).

In an example embodiment, the features may be divided into five classes: (1) query features, (2) result features, (3) searcher features, (4) query/result features, and (5) searcher/result features. A query feature is one that is drawn from the query itself, such as in cases where the query identifies a specific attribute of a search result, such as a first name, last name, company, or title.

A result feature is one that is drawn from the candidate result itself, such as industry, whether the candidate is considered an open candidate, a job seeker score for the candidate, a number of endorsers of the candidate query/result features, whether the candidate is an influencer, a profile quality score, whether a position or education field is empty, a number of current positions/previous positions, and educations in the search result, a communication delivery score (indicating general willingness to receive communications, as self-reported by members), a quality member score (score calculated by computing how complete a member profile is), a member engagement score, a historical click through rate for the search result from all recruiters, a historical action rate (e.g., number of all actions taken on the result divided by number of impressions of the result in the last three months), number of communications received, number of communications accepted, a decision maker score, the amount of time since the candidate indicated he or she is an open candidate, and whether the candidate has applied for a job.

A searcher feature is one that is drawn from information about the searcher him or herself, such as industry, historical rate of selection of result, and location.

A query/result feature is one that is drawn from a combination of the query and the candidate result, such as number of terms in the query that match some text in the candidate result; number of terms in the query that match specific text fields in the candidate result; the fraction of terms in the query that match some text in the candidate result; the fraction of terms in the query that match specific text fields in the candidate result; the frequency that terms in the query match some text in the candidate result; the frequency that terms in the query match specific text fields in the candidate result; if the query contains a first name and a last name and the candidate result is an influencer, then whether the candidate results matches the first name and last name; whether a position in the query matches a position in the candidate result; whether a title in the query matches a title in the candidate result; Term-Frequency-Inverse Document Frequency score; BM25F score; relative importance of matched terms with respect to the query itself and the fields of the candidate result (e.g., number of matched terms {circumflex over ( )}2/(number of terms in the query*number of terms in the field), generated affinity score created by a product of the query and member embeddings (similarity between search query and candidate result); raw query and candidate result matching features for schools; BM25 for current position summary divided by past position summary; clicks by candidate on advertisements from company employing searcher, if the query is a sample job posting; similarity between fields in the job posting and fields in the candidate result; similarity score between the candidate result and weighted query terms, with the weights learned online; and deep embedding features for title, skill, company, and field of study.

A searcher/result feature is one that is drawn from a combination of the searcher and the candidate result, such as network distance (social network degrees of separation between the searcher and the candidate result), number of common connections, location match, number of matching fields (e.g., current company, past company, school, industry), match score (number of matches squared divided by the product of searcher field size and result field size), recruiter-candidate affinity score (using, e.g., history data for sends and accepts between searcher and candidate result), number of common groups, and company interest score.

In an example embodiment, the neural network 412 is a DCNN. A DCNN is a machine-learning model that effectively infers non-linear relationships between a homogeneous input field and desired outputs, which are either categorical classes or scalars. The DCNN is a model that maps inputs to outputs using a sequence of so-called convolutional layers of artificial neurons. The DCNN may be trained by presenting it with a large number (e.g., greater than 10,000) of sample data and labels. It is trained to minimize the discrepancy (or “loss”) between the mode's output and the desired output. After the training, the model may be applied to new input images to produce a useful prediction of the professionalism levels of the new input images.

The DCNN is designed to learn not only scores for candidates, but also to learn the feature hierarchy by defining a number of layers. The process of inference involves taking a given input, applying a sequence of mathematical functions called layers, and calculating the functions on the input data. Each layer extracts features from the output of a previous layer, and all layers are trained jointly. The layer-based architecture is why it is termed a “deep” convolutional neural network.

In an example embodiment, five different types of layers are utilized. The first four layers are the convolutional layer, the nonlinearity layer, the pooling layer, and the classification layer (although the classification is just a special case of convolution followed by “softmax”). These first four layers may be considered to be a stage, and the DCNN may actually be designed to have any number of these stages. Once the stages are all complete, a loss layer is used. FIG. 5 is a diagram illustrating a DCNN 500, in accordance with an example embodiment. The DCNN 500 may be, in some example embodiments, the neural network 412 of FIG. 4. Here, two stages 502A, 502B are depicted.

The convolutional layers 504A, 504B are the core of the DCNN 500. Their parameters include a set of learnable filters that have a small receptive field but extend through the full depth of the input data. During a forward pass in a convolutional layer 504A, 504B, each filter is convolved across the features, computing the dot product between the entries of the filter and the input and producing a 2-dimensional activation map of that filter. As a result, the DCNN 500 learns filters that activate when they see some specific type of feature.

The feature maps for all filters can be stacked along the depth dimension to form the full volume output of the convolutional layers 504A, 504B.

The convolutional layers 504A, 504B apply mathematical operations called convolutionals. For two spatial dimensions and an indeterminate amount of non-spatial dimensions (referred to as “channels”), the convolutional is defined using the * operator as follows:

${y\left\lbrack {n,m,d} \right\rbrack} = {{x*f} = {\sum\limits_{o}{\sum\limits_{{j = {- M}},{k = {- N}}}^{{j = M},{k = N}}{{x\left\lbrack {n,m,0} \right\rbrack}{f_{d}\left\lbrack {{n - k},{m - j},o} \right\rbrack}}}}}$

The convolutional layers 504A, 504B will typically have some very small support, e.g., N=1 and M=1, such that g[n, m, d]=0 if |n|>1 or |m|>1.

It should be noted that the filters used in the convolutional layers 504A, 504B may be activated in a first iteration of the DCNN 500 and refined prior to each additional iteration, based on actions taken in other layers in the previous iteration, until some error term is minimized below a particular threshold. In one example embodiment, this may be accomplished through back propagation, which is described in more detail below.

The output of the convolutional layers 504A, 504B are sets of arrays called feature maps 506A-506C. Each feature map 506A-506C may be produced by a different filter and modified based on various functions in each stage. At the output, each feature map 506A-506C represents a particular feature extracted at all locations on the input and conditioned. The example in FIG. 5 is of a two-stage system, although one of ordinary skill in the art will recognize that more or fewer stages could be used while still being consistent with the present disclosure, and indeed as will be seen in an example embodiment, the number of stages may be dynamically determined at runtime to optimize results.

The nonlinearity layers 508A, 508B give the DCNN 500 greater expressive power in uncovering nonlinear relationships between input and output. Many different nonlinearities could be used in the nonlinearity layer, including sigmoid, tan h, and rectified linear function. For brevity, one example of nonlinearity will be described here: the rectified linear function. This function is defined by the following:

${y(x)} = \left\{ \begin{matrix} {{x\mspace{14mu}{if}\mspace{14mu} x} > 0} \\ {{0\mspace{14mu}{if}\mspace{14mu} x} < 0} \end{matrix} \right.$

The pooling layers 510A, 510B are applied to lower the input image's spatial dimensions while preserving some information from the input image. In other words, the pooling layers 510A, 510B do not actually do any of the learning, i.e., they are a fixed predefined operation that does not change as training progresses. Instead, they use the spatial dimensions of the problem. In one example embodiment, a decimation approach could be followed, where one out of every N samples along a spatial dimension is kept out. In another example embodiment, some local statistics may be used for pooling, such as max pooling, defined as:

${Y\left\lbrack {n,m,d} \right\rbrack} = {\max\limits_{{{n^{\prime}} < N},{{m^{\prime}} < M}}\;{x\left\lbrack {{n + n^{\prime}},{m + m^{\prime}},d} \right\rbrack}}$ where  N = M = 2.

When all the stages 502A, 502B are complete, a classification layer 512 is used to classify the image using the output of the final pooling layer 510B. As stated above, the classification layer 512 is actually a specialized convolutional layer containing a filter designed to produce the score from the volume output of the final pooling layer 510B. This filter applies a classification function having weights that may be refined in the same manner as the weights in the functions of the filters of the normal convolutional layers 504, 504B.

Back propagation involves calculating a gradient of a loss function (defined later) in a loss layer 514, with respect to a number of weights in the DCNN 500. The gradient is then fed to a method that updates the weights for the next iteration of the training of the DCNN 500 in an attempt to minimize the loss function, which uses a different plurality of sample data (unless there is a need to repeat, such as running out of sample data). Back propagation uses the labeled sample data in a batch of sample data that have been passed through the stages 502A, 502B in order to calculate the loss function gradient for the samples as a group (although, as will be seen later, the loss function may be modified dynamically to eliminate some of the samples from consideration).

Back propagation may include two aspects: propagation and weight update. In the propagation aspect, forward propagation of a training pattern's input images is performed through the DCNN 500 in order to generate the propagation's output activations (i.e., the images are passed through the stages 502A, 502B). Then, backward propagation of the propagation's output activations are performed through the DCNN 502 using a target specified by the training pattern in order to generate the deltas of all output.

In the weight update aspect, for each weight of each filter, the output delta and input activation are multiplied to obtain the gradient of the weight, and then a ratio of the gradient is subtracted from the weight. The ratio influences speed and quality of learning. The higher the ratio, the faster the training, but at the expense of accuracy.

Thus, these two aspects, including both the forward pass and the backward pass through the stages 502A, 502B are performed repeatedly until the error rate is below a particular threshold. An example of back propagation algorithms compatible with the DCNN 500 include, for example, gradient descent.

The use of the back propagation may be predicated on whether or not the combined error of the classification of the images in the batch of labeled sample data transgressed a preset error threshold. If the combined error is too great, then back propagation should occur to update and hopefully minimize the error for the next iteration, and a next iteration is performed with a subsequent batch of labeled sample data, until the combined error does not transgress the threshold.

As described above, the labeled output may be score for the data. The DCNN 500 outputs a vector that may be compared to the desired output of some loss function, such as the sum square error function:

${loss} = {\sum\limits_{i}\left( {{\hat{l}}_{i} - l_{i}} \right)^{2}}$

As described above, the process of training the DCNN 500 includes a number of different operations. FIG. 6 is a flow diagram illustrating a method 600 of training a DCNN 500, in accordance with an example embodiment. At operation 602, a batch of sample labeled data are fed to the DCNN 500 and the current model of the DCNN 500 produces an output. This output may be, for example, a score for each sample labeled datum. At operation 604, the loss layer 514 of the DCNN 500 calculates the error for the batch of sample data. This error may be, for example, a combination of the individual errors for each of the individual sample labeled data. At operation 606, weights inside the filters in the convolutional layers 504A, 504B (which also include the classification layer 512) are updated to minimize the loss, in accordance with the loss function defined in the loss layer 514. At operation 608, it is determined if the error has been minimized, based on a defined validation set. This defined validation set may include an error threshold, and if that error threshold has been transgressed, then the error has not been minimized and the process repeats back to operation 602 for the next batch of sample labeled images. If the error has been minimized (the threshold has not been transgressed), then the DCNN has been trained.

In an example embodiment, the defined validation set is based on a stochastic gradient descent (SGD) function. SGD comprises the following steps:

-   -   1. Randomly select a small number of samples from the training         set;     -   2. Feed the selected samples through all the layers 506-512 in         the DCNN 500 until the current error is calculated for each         feature map 506A-506C;     -   3. Update the weights in the convolutional layer 506 with a         gradient descent rule:         w _(new) =w _(old)−α∇error(w _(old))         where w is the weight.

FIG. 7 is a block diagram illustrating a neural network 700, in accordance with an example embodiment. The neural network contains hidden layers 702, an embedding layer 704, and a rescaling layer 706. The embedding layer 704 takes embeddings of features as input, including, for example, candidate ID features 708 and query ID features 710. These embeddings may have been assigned originally via a hand-created taxonomy. The embedding layer 704 then ingests the embeddings to automatically fine tune them to maximize a specified objective.

Furthermore, since the embedding layer 704 uses multiple types of input features, in situations where there is a shared feature between the different input feature types, in an example embodiment embedding weights that have been learned/fine-tuned may then also be shared. This results in fewer parameters being fed to the neural network, which improves performance metrics and also prevents overfitting.

In a further example embodiment, a rescaling transformation for each input feature is learned and applied to the values for the input features during the training process. This helps solve a technical issue that arises when the input features have widely differing scales. Since neural networks use vector combinations, such widely differing scales could throw off the training process. These transformations are learned on-the-fly during the training process. The transformations are learned and applied in the rescaling layer 706.

Output from both the rescaling layer 706 and embedding layer 704 is fed to the hidden layers 702, which also get trained. Once these layers have all been trained to a point at which some objective function is optimized, the model training is complete and the neural network 700 may be utilized to output scores for input data.

In some example embodiments, these techniques may be applied to search results that are member profiles or other content uniquely associated with particular members. For example, a recruiter may be the searcher of member profiles in an online service. In such instances, the first machine learned model is trained to determine the probability that the recruiter will select a given member if the member's profile was returned as a search result, while the second machine learned model is trained to determine the probability that the member corresponding to the member profile will respond to the recruiter if contacted.

For purposes of this document, a member of an online service may be referred to as a candidate. A search result presented to a recruiter may be referred to as an impression. A communication from the recruiter to a candidate may be referred to as a send. A communication from the candidate to the recruiter in response to the send may be referred to as an accept. Generally, in the recruiter/member case, the probabilities may be described as: p(send,accept|impression)→p(accept|send)·p(send|impression)

In an example embodiment, a feature vector may be created for each potential search result to be evaluated. The details of the feature vector will be described in more detail below. The feature vector is used as input to the first machine learned model and the second machine learned model to generate, for example, the probabilities on the right side of the above equation. In some example embodiments, this may be reflected mathematically as follows:

${p\left( {z = \left. 1 \middle| x \right.} \right)} = {{{{p\left( {{z = \left. 1 \middle| x \right.};{y = 1}} \right)}*{p\left( {y = \left. 1 \middle| x \right.} \right)}} \sim} = {{\smallsetminus {hat}}\left\{ p \right\}{\left( {{z = \left. 1 \middle| x \right.};{y = 1}} \right)\hat{}a}*{\smallsetminus {hat}}\left\{ p \right\}{\left( {y = \left. 1 \middle| x \right.} \right)\hat{}b}}}$ where x is the feature vector for an impression, y is a binary variable indicating whether there is a send or not, and z is a binary variable indicating whether there is an accept.

p(⋅) represents probability of an event and \hat{p} denotes empirical estimates of p. The second step is an overrelaxation. Since \hat{p} is an inexact approximation, overrelaxation helps us alleviate the effect of inaccuracy in approximation. Overrelaxation, together with score probabilistic calibration, gives the flexibility to use models which can achieve better area under the curve of receiver operating characteristic in prediction but not better cross-entropy. In some example embodiments, alpha (a) in the following formula is around 0.5. Thus, the order preserving transform becomes: log p(z=1|x)=a*log p(z=1|x;y=1)+b*log p(y=1|x)

It should be noted that the term “social” as used throughout this document should be interpreted broadly to cover any type of grouping of online members of a service in which communications can be sent through the service. This is in contrast to a grouping of online members of services where communications are only sent through external means (e.g., traditional email, phone call, etc.) and also in contrast to groupings of general Internet users.

As described briefly above, candidates are ranked in accordance to the scoring during both training and runtime of the neural network. During training, this ranking of an entire list of candidates is evaluated to determine a listwise loss defined over the whole list of candidates. This listwise loss is evaluated using the loss function in the neural network to train parameters in subsequent iterations. Examples of Listwise loss functions include Softmax, Mean Squared, List Maximum Likelihood Estimation (MLE), and Approximate Normalized Discounted Cumulative Gain (NDCG).

FIG. 8 is a flow diagram illustrating a method 800 for returning search results in an online computer system, in accordance with an example embodiment. In a training phase, at operation 802, a plurality of sample member profiles of members of the online service are retrieved along with a plurality of sample member labels and activity and usage information pertaining to actions taken by those members on the online service. Then a loop is begun for each member profile in the plurality of sample member profiles. At operation 804, the first sample member profile and the activity and usage information pertaining to actions taken by that member on the online service are parsed to extract a first set of features. At operation 806, a query is parsed to extract a set of one or more query features. Then, at operation 808, sample member labels, the extracted first set of features, and the set of one or more query features are fed into a first machine learning algorithm to train the neural network to output scores reflective of a probability that a searcher will select a potential search result corresponding to the first sample member profile and a probability that a member corresponding to the first sample member profile will respond to a communication from a searcher having the second sample member profile. At operation 810, it is determined if there are any more sample member profiles in the plurality of sample member profiles. If so, then the method 800 loops back to operation 804 for the next sample member profile.

If not, then at operation 812 a listwise loss function is evaluated using the outputted scores from operation 808 to determine if the listwise loss function has been optimized. If not, then at operation 814, coefficients applied to values of features by the neural network are modified and the method 800 repeats to operation 808. Once the listwise loss function has been optimized, the training phase is complete and a runtime phase begins. At operation 816, a plurality of candidate search results is retrieved in response to a query corresponding to a searcher. Then a loop is begun for each candidate search result in the plurality of candidate search results. At operation 818, activity and usage information for a member corresponding to the candidate search result is obtained. At operation 820, the candidate search result and the activity and usage information for the member are parsed to extract a second set of one or more features. At operation 822, the query is parsed to extract a set of one or more query features. At operation 824, the extracted sets of features are fed into the neural network, which outputs a score. At operation 826, it is determined if there are any more candidate search results in the plurality of candidate search results. If so, then the method 800 loops back to operation 818 for the next candidate search result.

If not, then at operation 828, the plurality of candidate search results are ranked by their corresponding combined probabilities. At operation 830, one or more of the plurality of candidate search results are returned based on the ranking.

FIG. 9 is a screen capture illustrating a graphical user interface 900 for displaying results of the ranking performed in FIG. 8. Here, one or more candidates 902, 904, 906 are rendered graphically in order of the ranking.

FIG. 10 is a block diagram 1000 illustrating an architecture of software 1002, which can be installed on any one or more of the devices described above. FIG. 10 is merely a non-limiting example of a software architecture, and it will be appreciated that many other architectures can be implemented to facilitate the functionality described herein. In various embodiments, the software 1002 is implemented by hardware such as a machine 1100 of FIG. 11 that includes processors 1110, memory 1130, and input/output (I/O) components 1150. In this example architecture, the software 1002 can be conceptualized as a stack of layers where each layer may provide a particular functionality. For example, the software 1002 includes layers such as an operating system 1004, libraries 1006, frameworks 1008, and applications 1010. Operationally, the applications 1010 invoke API calls 1012 through the software stack and receive messages 1014 in response to the API calls 1012, consistent with some embodiments.

In various implementations, the operating system 1004 manages hardware resources and provides common services. The operating system 1004 includes, for example, a kernel 1020, services 1022, and drivers 1024. The kernel 1020 acts as an abstraction layer between the hardware and the other software layers, consistent with some embodiments. For example, the kernel 1020 provides memory management, processor management (e.g., scheduling), component management, networking, and security settings, among other functionality. The services 1022 can provide other common services for the other software layers. The drivers 1024 are responsible for controlling or interfacing with the underlying hardware, according to some embodiments. For instance, the drivers 1024 can include display drivers, camera drivers, BLUETOOTH® or BLUETOOTH® Low Energy drivers, flash memory drivers, serial communication drivers (e.g., Universal Serial Bus (USB) drivers), WI-FI® drivers, audio drivers, power management drivers, and so forth.

In some embodiments, the libraries 1006 provide a low-level common infrastructure utilized by the applications 1010. The libraries 1006 can include system libraries 1030 (e.g., C standard library) that can provide functions such as memory allocation functions, string manipulation functions, mathematic functions, and the like. In addition, the libraries 1006 can include API libraries 1032 such as media libraries (e.g., libraries to support presentation and manipulation of various media formats such as Moving Picture Experts Group-4 (MPEG4), Advanced Video Coding (H.264 or AVC), Moving Picture Experts Group Layer-3 (MP3), Advanced Audio Coding (AAC), Adaptive Multi-Rate (AMR) audio codec, Joint Photographic Experts Group (JPEG or JPG), or Portable Network Graphics (PNG)), graphics libraries (e.g., an OpenGL framework used to render in two dimensions (2D) and three dimensions (3D) in a graphic content on a display), database libraries (e.g., SQLite to provide various relational database functions), web libraries (e.g., WebKit to provide web browsing functionality), and the like. The libraries 1006 can also include a wide variety of other libraries 1034 to provide many other APIs to the applications 1010.

The frameworks 1008 provide a high-level common infrastructure that can be utilized by the applications 1010, according to some embodiments. For example, the frameworks 1008 provide various GUI functions, high-level resource management, high-level location services, and so forth. The frameworks 1008 can provide a broad spectrum of other APIs that can be utilized by the applications 1010, some of which may be specific to a particular operating system or platform.

In an example embodiments, the applications 1010 include a home application 1050, a contacts application 1052, a browser application 1054, a book reader application 1056, a location application 1058, a media application 1060, a messaging application 1062, a game application 1064, and a broad assortment of other applications such as a third-party application 1066. According to some embodiments, the applications 1010 are programs that execute functions defined in the programs. Various programming languages can be employed to create one or more of the applications 1010, structured in a variety of manners, such as object-oriented programming languages (e.g., Objective-C, Java, or C++) or procedural programming languages (e.g., C or assembly language). In a specific example, the third-party application 1066 (e.g., an application developed using the ANDROID™ or IOS™ software development kit (SDK) by an entity other than the vendor of the particular platform) may be mobile software running on a mobile operating system such as IOS™, ANDROID™, WINDOWS® Phone, or another mobile operating system. In this example, the third-party application 1066 can invoke the API calls 1012 provided by the operating system 1004 to facilitate functionality described herein.

FIG. 11 illustrates a diagrammatic representation of a machine 1100 in the form of a computer system within which a set of instructions may be executed for causing the machine to perform any one or more of the methodologies discussed herein, according to an example embodiment. Specifically, FIG. 11 shows a diagrammatic representation of the machine 1100 in the example form of a computer system, within which instructions 1116 (e.g., software, a program, an application, an applet, an app, or other executable code) for causing the machine 1100 to perform any one or more of the methodologies discussed herein may be executed. For example the instructions 1116 may cause the machine 1100 to execute the method 800 of FIG. 8. Additionally, or alternatively, the instructions 1116 may implement FIGS. 1-9, and so forth. The instructions 1116 transform the general, non-programmed machine 1100 into a particular machine 1100 programmed to carry out the described and illustrated functions in the manner described. In alternative embodiments, the machine 1100 operates as a standalone device or may be coupled (e.g., networked) to other machines. In a networked deployment, the machine 1100 may operate in the capacity of a server machine or a client machine in a server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine 1100 may comprise, but not be limited to, a server computer, a client computer, a PC, a tablet computer, a laptop computer, a netbook, a set-top box (STB), a PDA, an entertainment media system, a cellular telephone, a smart phone, a mobile device, a wearable device (e.g., a smart watch), a smart home device (e.g., a smart appliance), other smart devices, a web appliance, a network router, a network switch, a network bridge, or any machine capable of executing the instructions 1116, sequentially or otherwise, that specify actions to be taken by the machine 1100. Further, while only a single machine 1100 is illustrated, the term “machine” shall also be taken to include a collection of machines 1100 that individually or jointly execute the instructions 1116 to perform any one or more of the methodologies discussed herein.

The machine 1100 may include processors 1110, memory 1130, and I/O components 1150, which may be configured to communicate with each other such as via a bus 1102. In an example embodiment, the processors 1110 (e.g., a Central Processing Unit (CPU), a Reduced Instruction Set Computing (RISC) processor, a Complex Instruction Set Computing (CISC) processor, a Graphics Processing Unit (GPU), a Digital Signal Processor (DSP), an ASIC, a Radio-Frequency Integrated Circuit (RFIC), another processor, or any suitable combination thereof) may include, for example, a processor 1112 and a processor 1114 that may execute the instructions 1116. The term “processor” is intended to include multi-core processors that may comprise two or more independent processors (sometimes referred to as “cores”) that may execute instructions contemporaneously. Although FIG. 11 shows multiple processors 1110, the machine 1100 may include a single processor with a single core, a single processor with multiple cores (e.g., a multi-core processor), multiple processors with a single core, multiple processors with multiples cores, or any combination thereof.

The memory 1130 may include a main memory 1132, a static memory 1134, and a storage unit 1136, all accessible to the processors 1110 such as via the bus 1102. The main memory 1130, the static memory 1134, and storage unit 1136 store the instructions 1116 embodying any one or more of the methodologies or functions described herein. The instructions 1116 may also reside, completely or partially, within the main memory 1132, within the static memory 1134, within the storage unit 1136, within at least one of the processors 1110 (e.g., within the processor's cache memory), or any suitable combination thereof, during execution thereof by the machine 1100.

The I/O components 1150 may include a wide variety of components to receive input, provide output, produce output, transmit information, exchange information, capture measurements, and so on. The specific I/O components 1150 that are included in a particular machine will depend on the type of machine. For example, portable machines such as mobile phones will likely include a touch input device or other such input mechanisms, while a headless server machine will likely not include such a touch input device. It will be appreciated that the I/O components 1150 may include many other components that are not shown in FIG. 11. The I/O components 1150 are grouped according to functionality merely for simplifying the following discussion and the grouping is in no way limiting. In various example embodiments, the I/O components 1150 may include output components 1152 and input components 1154. The output components 1152 may include visual components (e.g., a display such as a plasma display panel (PDP), a light emitting diode (LED) display, a liquid crystal display (LCD), a projector, or a cathode ray tube (CRT)), acoustic components (e.g., speakers), haptic components (e.g., a vibratory motor, resistance mechanisms), other signal generators, and so forth. The input components 1154 may include alphanumeric input components (e.g., a keyboard, a touch screen configured to receive alphanumeric input, a photo-optical keyboard, or other alphanumeric input components), point-based input components (e.g., a mouse, a touchpad, a trackball, a joystick, a motion sensor, or another pointing instrument), tactile input components (e.g., a physical button, a touch screen that provides location and/or force of touches or touch gestures, or other tactile input components), audio input components (e.g., a microphone), and the like.

In further example embodiments, the I/O components 1150 may include biometric components 1156, motion components 1158, environmental components 1160, or position components 1162, among a wide array of other components. For example, the biometric components 1156 may include components to detect expressions (e.g., hand expressions, facial expressions, vocal expressions, body gestures, or eye tracking), measure biosignals (e.g., blood pressure, heart rate, body temperature, perspiration, or brain waves), identify a person (e.g., voice identification, retinal identification, facial identification, fingerprint identification, or electroencephalogram-based identification), and the like. The motion components 1158 may include acceleration sensor components (e.g., accelerometer), gravitation sensor components, rotation sensor components (e.g., gyroscope), and so forth. The environmental components 1160 may include, for example, illumination sensor components (e.g., photometer), temperature sensor components (e.g., one or more thermometers that detect ambient temperature), humidity sensor components, pressure sensor components (e.g., barometer), acoustic sensor components (e.g., one or more microphones that detect background noise), proximity sensor components (e.g., infrared sensors that detect nearby objects), gas sensors (e.g., gas detection sensors to detection concentrations of hazardous gases for safety or to measure pollutants in the atmosphere), or other components that may provide indications, measurements, or signals corresponding to a surrounding physical environment. The position components 1162 may include location sensor components (e.g., a GPS receiver component), altitude sensor components (e.g., altimeters or barometers that detect air pressure from which altitude may be derived), orientation sensor components (e.g., magnetometers), and the like.

Communication may be implemented using a wide variety of technologies. The I/O components 1150 may include communication components 1164 operable to couple the machine 1100 to a network 1180 or devices 1170 via a coupling 1182 and a coupling 1172, respectively. For example, the communication components 1164 may include a network interface component or another suitable device to interface with the network 1180. In further examples, the communication components 1164 may include wired communication components, wireless communication components, cellular communication components, Near Field Communication (NFC) components, Bluetooth® components (e.g., Bluetooth® Low Energy), Wi-Fi® components, and other communication components to provide communication via other modalities. The devices 1170 may be another machine or any of a wide variety of peripheral devices (e.g., a peripheral device coupled via a USB).

Moreover, the communication components 1164 may detect identifiers or include components operable to detect identifiers. For example, the communication components 1164 may include Radio Frequency Identification (RFID) tag reader components, NFC smart tag detection components, optical reader components (e.g., an optical sensor to detect one-dimensional bar codes such as Universal Product Code (UPC) bar code, multi-dimensional bar codes such as Quick Response (QR) code, Aztec code, Data Matrix, Dataglyph, MaxiCode, PDF417, Ultra Code, UCC RSS-2D bar code, and other optical codes), or acoustic detection components (e.g., microphones to identify tagged audio signals). In addition, a variety of information may be derived via the communication components 1164, such as location via Internet Protocol (IP) geolocation, location via Wi-Fi® signal triangulation, location via detecting an NFC beacon signal that may indicate a particular location, and so forth.

Executable Instructions and Machine Storage Medium

The various memories (i.e., 1130, 1132, 1134, and/or memory of the processor(s) 1110) and/or storage unit 1136 may store one or more sets of instructions and data structures (e.g., software) embodying or utilized by any one or more of the methodologies or functions described herein. These instructions (e.g., the instructions 1116), when executed by processor(s) 1110, cause various operations to implement the disclosed embodiments.

As used herein, the terms “machine-storage medium,” “device-storage medium,” “computer-storage medium” mean the same thing and may be used interchangeably in this disclosure. The terms refer to a single or multiple storage devices and/or media (e.g., a centralized or distributed database, and/or associated caches and servers) that store executable instructions and/or data. The terms shall accordingly be taken to include, but not be limited to, solid-state memories, and optical and magnetic media, including memory internal or external to processors. Specific examples of machine-storage media, computer-storage media and/or device-storage media include non-volatile memory, including by way of example semiconductor memory devices, e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), FPGA, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The terms “machine-storage media,” “computer-storage media,” and “device-storage media” specifically exclude carrier waves, modulated data signals, and other such media, at least some of which are covered under the term “signal medium” discussed below.

Transmission Medium

In various example embodiments, one or more portions of the network 1180 may be an ad hoc network, an intranet, an extranet, a VPN, a LAN, a WLAN, a WAN, a WWAN, a MAN, the Internet, a portion of the Internet, a portion of the PSTN, a plain old telephone service (POTS) network, a cellular telephone network, a wireless network, a Wi-Fi® network, another type of network, or a combination of two or more such networks. For example, the network 1180 or a portion of the network 1180 may include a wireless or cellular network, and the coupling 1182 may be a Code Division Multiple Access (CDMA) connection, a Global System for Mobile communications (GSM) connection, or another type of cellular or wireless coupling. In this example, the coupling 1182 may implement any of a variety of types of data transfer technology, such as Single Carrier Radio Transmission Technology (1×RTT), Evolution-Data Optimized (EVDO) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for GSM Evolution (EDGE) technology, third Generation Partnership Project (3GPP) including 3G, fourth generation wireless (4G) networks, Universal Mobile Telecommunications System (UMTS), High Speed Packet Access (HSPA), Worldwide Interoperability for Microwave Access (WiMAX), Long Term Evolution (LTE) standard, others defined by various standard-setting organizations, other long range protocols, or other data transfer technology.

The instructions 1116 may be transmitted or received over the network 1180 using a transmission medium via a network interface device (e.g., a network interface component included in the communication components 1164) and utilizing any one of a number of well-known transfer protocols (e.g., HTTP). Similarly, the instructions 1116 may be transmitted or received using a transmission medium via the coupling 1172 (e.g., a peer-to-peer coupling) to the devices 1170. The terms “transmission medium” and “signal medium” mean the same thing and may be used interchangeably in this disclosure. The terms “transmission medium” and “signal medium” shall be taken to include any intangible medium that is capable of storing, encoding, or carrying the instructions 1116 for execution by the machine 1100, and includes digital or analog communications signals or other intangible media to facilitate communication of such software. Hence, the terms “transmission medium” and “signal medium” shall be taken to include any form of modulated data signal, carrier wave, and so forth. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a matter as to encode information in the signal.

Computer-Readable Medium

The terms “machine-readable medium,” “computer-readable medium,” and “device-readable medium” mean the same thing and may be used interchangeably in this disclosure. The terms are defined to include both machine-storage media and transmission media. Thus, the terms include both storage devices/media and carrier waves/modulated data signals. 

What is claimed is:
 1. A system for returning search results in an online computer system, the system comprising: a non-transitory computer readable medium having instructions stored thereon, which, when executed by a processor, cause the system to: retrieve a plurality of sample member profiles of members of an online service, a plurality of sample member labels, and activity and usage information pertaining to actions taken by those members on the online service; for each sample member profile in the plurality of sample member profiles: parse the sample member profile and the activity and usage information pertaining to actions taken by a member corresponding to the sample member profile on the online service to extract a first set of one or more features; parse an associated query to extract one or more query features; and feed sample member labels, the extracted first set of one or more features and the extracted one or more query features into a first machine learning algorithm to train a neural network to output a score indicative of a probability that a searcher will select a potential search result corresponding to the sample member profile and a probability that a member corresponding to the sample member profile will respond to a communication from the searcher, the neural network containing an embedding layer that assigns an initial embedding to a value of a feature, the initial embedding being a representation of the value in a dimensional space, and, during training of the neural network, adjusts the initial embedding for the value of the feature, wherein the embedding layer is designed to share embeddings across sets of features.
 2. The system of claim 1, wherein the instructions further cause the system to: obtain a plurality of candidate search results in response to a query corresponding to a searcher; obtain a member profile, in the online service, corresponding to the searcher; for each candidate search result from the plurality of candidate search results: obtain activity and usage information for a member corresponding to the candidate search result; parse the candidate search result, the activity and usage information for the member corresponding to the candidate search result, and the member profile corresponding to the searcher to extract a second set of one or more features and a third set of one or more features; parse the query to extract one or more query features; and feed the extracted second set of one or more features, the extracted third set of one or more features, and the extracted one or more query features into the neural network to output a score for the candidate search result; rank the plurality of candidate search results by their corresponding scores; and return one or more of the plurality of candidate search results based on the ranking.
 3. The system of claim 1, wherein the neural network further comprises a rescaling layer, the rescaling layer learning rescaling transformations for one or more features during the training of the neural network.
 4. The system of claim 1, wherein the neural network further contains one or more hidden layers.
 5. The system of claim 1, wherein the neural network is a deep neural network.
 6. The system of claim 1, wherein the neural network is a convolutional neural network.
 7. A computer-implemented method for returning search results in an online computer system, the method comprising: retrieving a plurality of sample member profiles of members of an online service, a plurality of sample member labels, and activity and usage information pertaining to actions taken by those members on the online service; for each sample member profile in the plurality of sample member profiles: parsing the sample member profile and the activity and usage information pertaining to actions taken by a member corresponding to the sample member profile on the online service to extract a first set of one or more features; parsing an associated query to extract one or more query features; and feeding sample member labels, the extracted first set of one or more features and the extracted one or more query features into a first machine learning algorithm to train a neural network to output a score indicative of a probability that a searcher will select a potential search result corresponding to the sample member profile and a probability that a member corresponding to the sample member profile will respond to a communication from the searcher, the neural network containing an embedding layer that assigns an initial embedding to a value of a feature, the initial embedding being a representation of the value in a dimensional space, and, during training of the neural network, adjusts the initial embedding for the value of the feature, wherein the embedding layer is designed to share embeddings across sets of features.
 8. The method of claim 7, further comprising: obtaining a plurality of candidate search results in response to a query corresponding to a searcher; obtaining a member profile, in the online service, corresponding to the searcher; for each candidate search result from the plurality of candidate search results: obtaining activity and usage information for a member corresponding to the candidate search result; parsing the candidate search result, the activity and usage information for the member corresponding to the candidate search result, and the member profile corresponding to the searcher to extract a second set of one or more features and a third set of one or more features; parsing the query to extract one or more query features; and feeding the extracted second set of one or more features, the extracted third set of one or more features, and the extracted one or more query features into the neural network to output a score for the candidate search result; ranking the plurality of candidate search results by their corresponding scores; and returning one or more of the plurality of candidate search results based on the ranking.
 9. The method of claim 7, wherein the neural network further comprises a rescaling layer, the rescaling layer learning rescaling transformations for one or more features during the training of the neural network.
 10. The method of claim 7, wherein the neural network further contains one or more hidden layers.
 11. The method of claim 7, wherein the neural network is a deep neural network.
 12. The method of claim 7, wherein the neural network is a convolutional neural network.
 13. A non-transitory machine-readable storage medium comprising instructions, which when implemented by one or more machines, cause the one or more machines to perform operations comprising: retrieving a plurality of sample member profiles of members of an online service, a plurality of sample member labels, and activity and usage information pertaining to actions taken by those members on the online service; for each sample member profile in the plurality of sample member profiles: parsing the sample member profile and the activity and usage information pertaining to actions taken by a member corresponding to the sample member profile on the online service to extract a first set of one or more features; parsing an associated query to extract one or more query features; and feeding sample member labels, the extracted first set of one or more features and the extracted one or more query features into a first machine learning algorithm to train a neural network to output a score indicative of a probability that a searcher will select a potential search result corresponding to the sample member profile and a probability that a member corresponding to the sample member profile will respond to a communication from the searcher, the neural network containing an embedding layer that assigns an initial embedding to a value of a feature, the initial embedding being a representation of the value in a dimensional space, and, during training of the neural network, adjusts the initial embedding for the value of the feature, wherein the embedding layer is designed to share embeddings across sets of features.
 14. The non-transitory machine-readable storage medium of claim 13, further comprising: obtaining a plurality of candidate search results in response to a query corresponding to a searcher; obtaining a member profile, in the online service, corresponding to the searcher; for each candidate search result from the plurality of candidate search results: obtaining activity and usage information for a member corresponding to the candidate search result; parsing the candidate search result, the activity and usage information for the member corresponding to the candidate search result, and the member profile corresponding to the searcher to extract a second set of one or more features and a third set of one or more features; parsing the query to extract one or more query features; and feeding the extracted second set of one or more features, the extracted third set of one or more features, and the extracted one or more query features into the neural network to output a score for the candidate search result; ranking the plurality of candidate search results by their corresponding scores; and returning one or more of the plurality of candidate search results based on the ranking.
 15. The non-transitory machine-readable storage medium of claim 13, wherein the neural network further comprises a rescaling layer, the rescaling layer learning rescaling transformations for one or more features during the training of the neural network.
 16. The non-transitory machine-readable storage medium of claim 13, wherein the neural network further contains one or more hidden layers.
 17. The non-transitory machine-readable storage medium of claim 13, wherein the neural network is a deep neural network. 